1. Field of the Invention
The present invention relates to an electrophotographic apparatus using liquid toners and particularly to a liquid ink or toner containing an organoleptic odor maskant or odor neutralizer.
2. Background of the Art
Liquid toners used in electrophotographic printing systems and devices generally comprise of carrier liquid, polymeric binder, colorant, and an optional charge control agent. Liquid electrophotography is a process in which a charged photoreceptive element is struck with radiation, particularly light, causing the exposed areas to discharge to form a latent electrostatic image pattern. Liquid toner held in a developing station is transferred to the discharged areas, developing the latent electrostatic image. The developed image may then be transferred to a final image receptor, or to an intermediate transfer member, with subsequent transfer to a final image receptor. Since liquid carrier is not desired on the final printed substrate, it is necessary to remove the liquid at some time prior to the viewing availability of the final image. Without removal of the carrier, the image would be unlikely to be stable against abrasion, remaining in a soft or even liquid state.
The carrier liquid, which may be essentially odorless in small quantities in the liquid form of the toner or ink, may be found to be offensive under other circumstances. For example, the strength or nature of the odor may be undesirable in larger quantities of the carrier; as the toner (including the carrier liquid) is circulated through the developer station; or during the carrier liquid removal step (e.g., by evaporation), regardless of where that may take place.
In the electrophotographic printing apparatus, probably the greatest source of offensive or troublesome odors is in the step in which the carrier liquid is evaporated from or dried from the image after deposition on a surface. In many cases, this evaporation step occurs in a fusing apparatus, which not only serves to evaporate the solvent, but heats the toner particles, allowing them to flow into and bond with the paper and themselves. During fusing, the ink, comprising carrier liquid, is heated quickly to a high temperature, causing all or substantially all (by substantially all is meant the removal of that amount of the carrier that enables the image to meet stability requirements) carrier liquid to evaporate quickly. Depending on the temperature used to evaporate the carrier, tiny airborne droplets of aerosol mist (airborne carrier solvent) may be formed. This sudden influx of airborne carrier through either vapor or aerosol mist can have odors associated with it for many reasons. Either the carrier itself may have an odor, or the droplets pick up other materials from the ink which may have odors.
In some applications, it is desirable for ink to have a pleasant odor, or scent. Children's pens and markers, for example, are frequently infused with fruity and floral scents that tend to coordinate with the ink color selected. Balloons and cards are also printed with scented inks to give the articles a scent, without having to create the scent in the actual article.
U.S. Pat. No. 4,065,304 discloses a fruit-shaped ball point pen that emits the scent characteristic of its shape. U.S. Patent Application No. 20020011180 (Jan. 31, 2002) discloses water-based scented pens where the scent remains even when the ink is dry.
Other novelty uses for scented ink include children's coloring books that release fragrance when colored (U.S. Pat. No. 5,018,974), scented balloons (U.S. Pat. No. 5,577,947), scented pages (U.S. Pat. Nos. 5,975,675; and 5,970,300) and scented greeting cards (U.S. Pat. No. 6,261,347).
Dry toners often have a problem with the smell of styrene or other unpleasant odors and various means are known for reducing or eliminating those smells (U.S. Pat. Nos. 5,126,2224; 5,521,268; 6,157,072; and U.S. Patent Application No. 20030022082). Ink jet scent additives are also known (U.S. Pat. Nos. 6,180,692; 6,123,757; and U.S. Patent Application Nos. 20030005853; 20030076393; and 20030094117).
Odors caused by ozone and other product ingredients are moderated by the use of a specific class of deodorant. The deodorant contains a plant extract preferably usable in the invention is prepared from green tea, the crushed raw leaf of green tea is immersed in ethanol. Thus obtained ethanol extract which contains a catechin, a vitamin, a sugar and an enzyme is filtered and concentrated to obtain the deodorant containing the plant extract relating to the invention.
Most of the instances in the prior art have been designed to impart a subjectively determined “pleasant” smell in a printing or writing apparatus or on an article on which such an apparatus prints. Little is known about odor neutralizing vectors or the technology behind eliminating unpleasant smells while leaving no or little fragrance behind.